They are better known as a bunch of grizzled rockers from Hertfordshire, whose hits including Smoke on the Water have sold millions of records. But next week the English rock band Deep Purple are to perform their most unlikely gig yet - in front of Russia's heavy metal grooving future president, Dmitry Medvedev.

The state gas firm Gazprom has booked the band to fly from the UK to Moscow to perform at a special concert celebrating the 15th anniversary of the utility. The concert is a thank-you to Medvedev, who steps down as Gazprom chairman next month after Russia's presidential elections.

Medvedev is a devoted DP fan. A former lawyer from St Petersburg, he also likes Black Sabbath. Last year he boasted that he had collected all of Deep Purple's many albums, telling an interviewer: "I've loved hard rock since my school days."

Next week's concert takes place inside the Kremlin's state palace, in a grandiose 1960s Soviet concert hall.

Yesterday Gazprom and the band's management declined to comment. But Reuters, citing industry sources, said the concert would be on February 11, attended by Medvedev and Vladimir Putin.

This is not Medvedev's first intimate Deep Purple encounter; he and 70 other political and business figures brought Joe Lynn Turner - who was lead singer for only one album - to Moscow for a concert last year, Russian media reported.

The efforts to play up Medvedev's heavy-metal credentials are part of a strategy to show that Russia's future leader is a regular guy. But most experts believe Medvedev will continue his predecessor's policies, despite his liberal reputation.

Putin endorsed Medvedev in December as his presidential successor, virtually guaranteeing him a landslide victory in the March 2 vote.